Residents in western Victoria have been told it is too late to leave as out-of-control bushfires rage in catastrophic conditions in the Grampians National Park.

People in Pomonal were warned at 2pm they could be affected “within the next two hours” by a fire at Bellfield, in the Grampians, with emergency conditions likely to heighten as the day went on.

There were also warnings for Bellfield, Bellfield Settlement, Halls Gap and Lake Fyans.

“I anticipate a warning level to increase in the next hour or so and residents need to be very aware the situation is rapidly developing,” Country Fire Authority chief officer Jason Heffernan said in an update on Tuesday afternoon.

Only moments later, he confirmed the Bellfield fire had been upgraded from “leave immediately” to “too late to leave”.

“We do expect [a] frontal system to move through. That will dramatically increase those winds and will also dramatically change the direction of the fires … The situation is very dynamic,” Heffernan said.

“We are not out of the woods. I expect another couple of hours of these severe fire conditions across the state and we need to make sure we
are ready, no matter where the fire may occur.”

Warnings were also issued for Dadswells Bridge, Laharum, Ledcourt, Roses Gap and Wartook for an out-of-control fire burning at Mount Stapylton.

Grampians National Park was closed on Tuesday because of the catastrophic fire risk threatening parts of Victoria.

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In addition, a wild storm crossing Victoria brought down a major transmission line and tripped one of the state’s biggest coal-fired power station. Blackouts were expected as spot electricity prices soared.

Severe thunderstorms crossed an area spanning Melbourne to Bendigo, in central Victoria, on Tuesday afternoon. They brought heavy rain, strong winds and hailstones of up to 2.5 centimetres.

“Severe thunderstorms are likely to produce damaging winds and large hailstones in the warning area over the next several hours,” the Bureau of Meteorology said in its 2.15pm bulletin.

“Locations which may be affected include Bendigo, Seymour, Maryborough, Kyneton, Melbourne and Bacchus Marsh.”

Avalon Airport recorded a wind gust of 122km/hr at 2.19pm. Strong gusts in the area damaged high-voltage power lines at nearby Anakie.

Load-shedding began shortly after, as Loy Yang power station dropped offline.

The Australian Energy Market Operator issued a market alert declaring a “significant” power system event because of “multiple tripping of generation and transmission lines” on Tuesday afternoon. An estimated 50,000 people were without power by 4pm.

“In the last few hours, we have seen prolific thunderstorm and lightning activity develop across the state, particularly through central parts and Melbourne, but extending all the way back to the Mallee,” BOM’s Kevin Parkyn said.

“These storms are severe. Damaging winds, large hail have been reported and it is not over yet. We have a few hours for these storms to move through the west and central-west of the state, and they will continue through the night through eastern Victoria.”

Parkkyn said it was 41 degrees at Avalon ahead of the wind change, which brought a temperature drop down to 26 degrees as the thunderstorms closed in. They were expected to hit Melbourne in time for the afternoon peak.

“The wind changes are currently moving up through [Port Phillip Bay], hitting Geelong, across the Mornington Peninsula – and it is only probably an hour or so away from Melbourne,” he said.

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Earlier, Heffernan told ABC TV it was 29 degrees in Mildura and 27 degrees in Melbourne by 6am.

A catastrophic fire danger rating was declared for the Wimmera region, with authorities closely watching conditions in Rainbow, Warracknabeal, Minyip, Rupanyup and Murtoa.

“Those communities are of particular concern for firefighters today as conditions will be very, very nasty,” Heffernan said.

Extreme fire danger was forecast for the Mallee. There was a high danger rating for rest of the state, except for East Gippsland, and a total fire ban in much of the state.

Heffernan said it would be some of the most dangerous grassfire conditions since the Black Summer of 2019-20, which was one of Australia’s most intense and catastrophic fire seasons.

Meanwhile, Tasmanians were also warned to prepare for days of elevated fire danger.

Tasmania Fire Service deputy chief officer Matt Lowe said weather conditions combined with a dry landscape meant fires could spread easily and become difficult to control.

South Australians were also bracing for a hot, dry Tuesday and extreme fire conditions. Total fire bans were declared, with with extreme fire danger ratings for SA’s mid-north, Riverland and Murraylands.

The South Australian Country Fire Service said “very hazardous” fire weather conditions were predicted.

-with AAP